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Biomedical subjects

Y Zeng

Publications and source records attributed to Y Zeng.

At least 91 records · Page 5Linked to original sources
PubMed2000

[Occlusal contact force and stress analysis of molars with vertical root split].

OBJECTIVE: To study the induction of vertical root split by occlusal force. METHODS: 1. The occlusal contact force was studied in 34 cases (39 teeth) by photocclusion. 2. The stress analysis for the first mandicular molar was studied by three-dimensional definite element. RESULTS: 1. The occlusal contact force didn't distribute balancedly in 26 cases (31 teeth) and the suffering teeth bore greater force. 2. The bucco-lingual central line of the mesial root canal wall underwent greater tensile stress when tooth bore load with 30 degrees angle to axis, or buccal-lingual lateral load or logitudinal occlusive load on the masial or distal cusp. CONCLUSION: The vertical root split of molar is associated with greater occlusal force and the stress that concentrated on the buccolingual central line of the mesial root wall for a long time.

Adult↗
PubMed2000

[Surgery for patients with primary liver cancer: report of 1,038 patients].

OBJECTIVE: To investigate methods for enhancing safety of and improving the survival in patients with primary liver cancer (PLC). METHODS: One thousand and thirty eight patients with PLC were treated in our hospital from January 1990 to December 1998. The early period group (from January 1990 to December 1996) consisted of 731 patients [312 patients (42.7%) receiving liver resection]; the late period group (from January 1997 to December 1998) included 307 patients [217 patients (70.7%) receiving liver resection]. RESULTS: The mortality within one month after hepatectomy was 2.24% in the early group and 0.74% in the late group. The 1-, 3- and 5-year survival rates were 73.1%, 54.2%, and 34.0% respectively in patients undergoing hepatectomy in the early group and 91.1%, 63.8% and 40.2% in the late group. CONCLUSIONS: Regular follow-up of high risk patients is helpful to discover small PLC. High proportion of small PLC, progress of perioperative management, and improvement of operative techniques including hepatopetal blood occlusion of half liver or in vitro-bypass through bio-pump during hepatectomy might be important approaches to enhance the safety of surgical treatment and improve the prognosis of patients with PLC.

Adolescent↗
PubMed2000

[Sentinel lymph node biopsy in breast cancer: value for predicting the status of axillary node].

OBJECTIVE: To evaluate feasibility and accuracy of intraoperative lymphatic mapping with sentinel lymphadenectomy (SLND) for predicting axillary status in patients with breast cancer. METHODS: Our study enrolled 52 patients with primary breast cancer, clinically and ultrasonographically negative axillae. Mapping procedures and SLND were performed using methylene blue injected at the primary breast cancer site followed by axillary lymph node dissection (ALND). Sentinel node (SN) was examined by using frozen sections intraoperatively and all of the axillary lymph nodes were evaluated pathologically (HE) after operation. RESULTS: Sentinel nodes were identified in 46 (88.5%) of 52 procedures and nodal status accurately predicted axillary in 44 (95.7%) of 46 cases. In 2 (4.3%) of 46 cases, the SN was false-negative. The overall sensitivity of the SN technique was 90.9%, with a specificity of 100%. The overall positive and negative predictive values were 100% and 92.3%, respectively. In 15 (75%) of 20 cases of clinically negatively and pathologically positive axillary, the SN was the only tumor-involved lymph node identified. CONCLUSION: Our study indicates that intraoperative lymphatic mapping using a vital dye and SLND can accurately predict the axillary status of primary breast cancer patients with clinically and ultrasonographically negative axillae.

Adult↗
PubMed2000

[Molecular diagnosis in a Korean family with thalassemia intermedia due to co-inheritance of triplicated alpha-globin genes (alphaalpha/alphaalphaalpha(anti 3.7)) and beta-thalassemia trait (IVS-II-1 G-->A)].

OBJECTIVE: To analyze the molecular abnormalities of beta-thalassemia intermedia in a Korean family with thalassemia intermedia. METHODS: Polymerase chain reaction (PCR), Southern blot hybridization and double strand DNA cycle sequencing were used to analyse alpha, beta and gamma globin gene organization. RESULTS: In the Korean family the interaction between a triplicated alpha-globin locus and a heterozygous beta-thalassemia gave rise to a clinical phenotype of thalassemia. The molecular defect was a heterozygosity for a single beta-thalassemia mutation (beta IVS-II-1 G-->A) and a triplicated alpha-globin gene (alphaalpha/alphaalphaalpha(anti 3.7)). CONCLUSION: Beta-thalassemia heterozygotes conjuncted with alpha-globin gene triplication was the major cause of the beta-thalassemia intermedia in this Korean family.

Adult↗
PubMed2000

[Study on lumbricus in promoting ligation hemorrhoidectomy postoperative wound healing].

OBJECTIVE: To investigate the effect of Lumbricus in promoting wound healing of ligation hemorrhoidectomy. METHODS: Spray the artificial grown fresh Lumbricus solution on the wound surface of the mixed hemorrhoid patients (treated group) after hemorrhoidectomy and also on wound of the experimental animals, and Lithospermum erythrorhizon medicated gauze was taken as control to observe the effect of treatment on wound healing and histologic change. RESULTS: The mean wound healing time of the treated group was 16.5 +/- 1.8 days, as compared to the control group (21.2 +/- 2.8 days), it was obviously shortened (P < 0.01), 3 days after medication, the growth of epidermis of the treated group was obviously more rapid than that of the control group, no wound infection and granulation hyperplasia were found. The experimental study showed that Lumbricus preparation could inhibit inflammation, bacteria such as Staphylococcus aureus, coli and proteus bacillus was inhibited. In comparison with the control group, the experimental group shortened the healing period for 4 days. On the 4th and 7th day, sacrificed rabbits' capillary count, vessel lumen endothelial cell count, and mesenchymal fibroblast count of the experimental group grower obviously than those of the control group, on the 4th day, the mesenchymal cell mitosis of the experimental group was higher than that of the control group, while on the 7th day, the cell nucleus mitotic index in the experimental group also was higher than that in the control group, from the 3rd day on, wound healing and granulation filling speed of the experimental group obviously more rapid than that of the control group. CONCLUSION: The Lumbricus preparation is cheap in price, easy to preserve, can be used in promoting wound healing, without any toxic and side-effects.

Adult↗
PubMed2000

[A study of the immune in formation of calcium bilirubinate gallstones in different rabbit models--the changes of the immunoglobulins in serum and bile and the immunoglobulins forming cells in the gallbladder mucoderm].

The changes of Ig-forming cells in the gallbladder mucoderm and the immunoglobulins in serum and bile were studied in the rabbit models. One hundred rabbits were randomly divided into the control group (Con, n = 10), simple biliary obstruction group (BO, n = 45) and biliary obstruction and infection group (BOI, n = 45). The results showed that the concentrations of serum immunoglobulin A (IgA) in BO and BOI groups increased remarkably in all phases (P < 0.001), The concentrations of serum IgG in both groups increased with the formation of gallstones. The IgA and IgG contents of bile samples in BO and BOI groups with negative bacterial culture were much higher than those of control group (P < 0.05), but the Ig content of bile with positive culture was slightly lower than that of the control group. Only a few Ig-forming cells were found in the gallbladder mucoderm of normal rabbits. The counts of Ig-forming cells in the mucoderm in BO group remained unchanged, but increased much higher in BOI group (P < 0.001), especially in IgG formation. This experiment demonstrates the immunoglobulins of serum and bile change significantly during the formation of gallstones. The Ig content of bile has a relationship with bacterial infection. IgA plays an important role in gallstone formation. The gallbladder of rabbit may be an important place of Ig-formation. The quantity of Ig forming cells in biliary tract may have a close relationship with the gallstone formation.

Animals↗
PubMed2000

[The correlation of serum levels of insulin-like growth factors and intrauterine growth: report of a study in rats].

This animal experiment was designed to investigate the relationship of the serum insulin-like growth factors (IGFs) with fetal intrauterine growth. The serum concentrations of IGF-I, -II in 21 fetal rats were measuerd and their relationships with fetal birth weight, length and tissue weights of brain, lung, liver were analysed respecively. The results showed that both of the serum concentrations of IGF-I, -II were positively correlated (P < 0.01) with fetal birth weight, length and tissue weights of brain, lung, liver respectively. These data suggest that both IGF-I and IGF-II may play an important role in fetal intrauterin growth and their decreased concentrations in serum may be factors contributing to fetal intrauterine growth retardation.

Animals↗
PubMed2000

[Experimental safety study using rats and mice irradiated with the complex field cure instrument].

The complex field cure instrument is a new medical instrument. The complex field is composed of several sorts of physical quantum fields. Mice and rats are continuously irradiated by the complex field for 20 days to 90 days. The result shows that WBC, Hb and PLT value of the animals irradiated with the instrument are more than the control group, and their biochemical index is normal. The internal organs of the experimental animals show no toxicity. The visceval coefficient (liver, spleen) of the experimental animals is more than the control group. The marrow micronucleas test is negative. The chromosome test show no distortion. All of the results have proved that the instrument produces no toxicity side effect. Application of the instrument is safe and reliable and it may increase immune function of the body.

Animals↗
PubMed2000

[Synthesis and DNA binding studies of Ruthenium complexes by spectra].

New Complexes Ru(bpy)2dppx2+ were synthesized. The binding of Ru(bpy)2dppx2+ to calf thymus DNA has been investigated by using electronic absorption and fluorescence spectra. The intercalation mode was proved to exist. The DNA leads to a dramatic enhancement of the photoluminescence of the drug at 599 nm (lambda ex = 471 nm) and absorption hypochromic effect and red shift. It was obvious that Ruthenium complexes may be used at a good DNA probe.

Animals↗
PubMed1999

[Biological characteristics of human fetal esophageal epithelial cell line immortalized by the E6 and E7 gene of HPV type 18].

OBJECTIVE: Biological features including proliferation, differentiation and cell death of SHEE cell line, an immortalized epithelium of the fetal esophageal epithelium induced by HPV 18 E6E7 AAV, were studied. METHODS: SHEE cell line being cultured for more than 50 passages, were cultured in 199 growth medium and were examined by light, electron and fluorescence microscopy for growth rate, morphological features and chromosome analysis, by flow cytometry for cell proliferative dynamics, by immunohistochemistry for Ki67 and cytokeratin, and by terminal DNA transferase label (TUNEL) for apoptosis. RESULTS: At the 20th passage, the SHEE cell remained monolayer, anchorage-dependent and attachment-inhibited growth. The growth curve showed proliferative phase 3-8th days, top-plate phase 9-10th days and attenuative phase after 10th days. Proliferative index(PIx) 34.0%, mitotic index (MI) 2.74% (1.20%-4.80%), apoptotic index (AI) 1.30%-6.90%, chromosome analysis mainly 46 (44-54/nucleus) and DNA distribution in diploidy were calculated and described. The tonofilament expression in cell cytoplasm by electron-microscopy and positive reaction of cytokeratin by immunochemistry showed differentiative character of squamous epithelium. The cell apoptosis occured in the proliferative phase and especially increased in attenuative phase. CONCLUSION: Of biological behaviors, the SHEE cells are close to the basal cells of their original fetal esophageal mucosa keeping proliferative and differentiative potency. This study suggests that the cell death (including cell apoptosis) may be an important factor in studying of cell growth regulation and it may be an research area for cellular biological behaviors.

Cell Division↗
PubMed1999

[Immortalization of human fetal esophageal epithelial cells induced by E6 and E7 genes of human papilloma virus 18].

OBJECTIVE: For studying the relationship between HPV and esophageal carcinoma, an immortalized human fetal esophageal epithelial cell line (SHEE) was established. METHODS: The human fetal esophageal tissues were cultured and infected with HPV 18 E6E7 AAV. It was examined by light- and electron-microscope for morphological changes, by PCR and FISH for detection of HPV E6E7 and by soft agar culture and nude mice inoculatior for dectecting tumor transformation. RESULTS: The cell line has become immortal and has propagated cntinuously for more than 50 passages. After a long-term culture, the phenotype keeps the characteristics of primary epithelial cells. They showed as monolayer growth and anchorage dependent growth without forming colonies in softagar. They were nontumorigenic in nude mice. SHEE cells contained tonofilaments in its cytoplasm by electron microscopic examination and showed cytokeratin positive in immunohistochemical procedure. So it shows that the cells are squamous epithelium in origin. The cell line contained the HPV 18 E6 and E7 genes by FISH and PCR assay. CONCLUSION: Establishment of the esophageal epithelial cell line SHEE successfully immortalized with HPV 18, E6E7, supports that the HPV18 may be related to the etiology of esophageal carcinoma. It will facilitate further research on etiology and pathogenesis of esophageal carcinoma.

Cell Division↗
PubMed1999

Phospholipid-subclass-specific partitioning of lipophilic ions in membrane-water systems.

Herein, we systematically investigate phospholipid-subclass-specific alterations in the partitioning of both cationic and anionic amphiphiles to identify the importance of ester, ether and vinyl ether linkages at the sn-1 position of phospholipids in the partitioning of charged amphiphiles. The results demonstrated that the membrane-water partition coefficient of a prototypic cationic amphiphile (i.e. 3,3'-dipropylthiadicarbocyanine iodide) was approximately 2.5 times higher in membranes comprised of plasmenylcholine in comparison with membranes comprised of either phosphatidylcholine or plasmanylcholine. In striking contrast, the membrane-water partition coefficient of a prototypic anionic amphiphile [i.e. bis-(1,3-dibutylbarbituric acid)trimethine oxonol] in membranes comprised of plasmenylcholine was approximately 2.5 times lower than that manifest in membranes comprised of phosphatidylcholine or plasmanylcholine. Utilizing theseexperimentally determined partition coefficients,the relative membrane dipole potential of membranes comprised of plasmenylcholine was calculated and found to be approximately 25 mV lower than in membranes comprised of phosphatidylcholine or plasmanylcholine. This lower membrane dipole potential in membranes comprised of plasmenylcholine is equivalent to the membrane potential induced by incorporation of approximately 25 mol% of anionic phospholipids in membranes comprised of phosphatidylcholine. Collectively, these results demonstrate that phospholipid-subclass-specific differences in the membrane dipole potential contribute to alterations in the partitioning of lipophilic ions in membrane bilayers comprised of distinct phospholipid subclasses. Moreover, they suggest that these physicochemical differences can be exploited to facilitate the targeting of charged lipophilic drugs to specific cells and subcellular membrane compartments.

Anions↗
PubMed1999

Rapid repression of maize invertases by low oxygen. Invertase/sucrose synthase balance, sugar signaling potential, and seedling survival.

We show here that invertase gene expression and the invertase-sucrose (Suc) synthase ratio decrease abruptly in response to low oxygen in maize root tips. In addition to aiding in the conservation of carbon and possibly ATP, this response has the potential to directly affect sugar signaling relative to carbon flux. Experiments were motivated by the potential for a reduced invertase/Suc synthase balance to alter the impact of respiratory and/or membrane carbon flux on sugar signaling. Maize (Zea mays L.) seedlings with 5-cm primary roots were exposed to anoxic (0% [v/v] O2), hypoxic (3% [v/v] O2), and aerobic conditions. Rapid repression of the Ivr1 and Ivr2 maize invertases by low oxygen was evident in root tips within 3 h at both the transcript and activity levels. The speed and extent of this response increased with the degree of oxygen deprivation and differed with genotypes. This decrease in expression also contrasted markedly to that of other genes for respiratory Suc metabolism, such as Suc synthases, which typically increased or remained constant. Although previous work showed that the contrasting effects of sugars on Suc synthase genes were reflected in their regulation by hypoxia and anoxia, the same was not observed for the differentially sugar-responsive invertases. Theoretically advantageous reductions in the invertase/Suc synthase balance thus resulted. However, where this response was extreme (an Oh43 inbred), total sucrolytic capacity dropped below an apparent minimum and root tip viability was reduced. Paradoxically, only Oh43 seedlings showed survival levels >80% (versus <50%) after extreme, long-term stress, suggesting a possible advantage for multiple means of reducing sink activity. Overall, our results demonstrate a rapid change in the regulation and balance of invertases and Suc synthases that could have an immediate impact on limiting the extent of Suc cleavage and reducing the extent of concomitant, hexose-based sugar signaling under low oxygen.

Enzyme Repression↗
PubMed1999

DNA damage and replication checkpoints in fission yeast require nuclear exclusion of the Cdc25 phosphatase via 14-3-3 binding.

In fission yeast as well as in higher eukaryotic organisms, entry into mitosis is delayed in cells containing damaged or unreplicated DNA. This is accomplished in part by maintaining the Cdc25 phosphatase in a phosphorylated form that binds 14-3-3 proteins. In this study, we generated a mutant of fission yeast Cdc25 that is severely impaired in its ability to bind 14-3-3 proteins. Loss of both the DNA damage and replication checkpoints was observed in fission yeast cells expressing the 14-3-3 binding mutant. These findings indicate that 14-3-3 binding to Cdc25 is required for fission yeast cells to arrest their cell cycle in response to DNA damage and replication blocks. Furthermore, the 14-3-3 binding mutant localized almost exclusively to the nucleus, unlike wild-type Cdc25, which localized to both the cytoplasm and the nucleus. Nuclear accumulation of wild-type Cdc25 was observed when fission yeast cells were treated with leptomycin B, indicating that Cdc25 is actively exported from the nucleus. Nuclear exclusion of wild-type Cdc25 was observed upon overproduction of Rad 24, one of the two fission yeast 14-3-3 proteins, indicating that one function of Rad 24 is to keep Cdc25 out of the nucleus. In support of this conclusion, Rad 24 overproduction did not alter the nuclear location of the 14-3-3 binding mutant. These results indicate that 14-3-3 binding contributes to the nuclear exclusion of Cdc25 and that the nuclear exclusion of Cdc25 is required for a normal checkpoint response to both damaged and unreplicated DNA.

14-3-3 Proteins↗
PubMed1999

Knowledge of HIV/AIDS among health care workers in China.

This study was designed to assess knowledge of AIDS among health professionals in China via a cross-sectional survey. A self-administered questionnaire requesting demographic characteristics and basic AIDS knowledge was given to health professionals in 11 provinces, cities, and autonomous regions. Questionnaires were completed by 1,400 of 1,500 (93%) health professionals surveyed. The percentages of correct answers ranged from 3% to 68%. Findings included that public health workers had more knowledge than clinicians; having attended training workshops was not associated with an adequate levels of knowledge; and knowledge differed by professional level and by the geographic region in which they worked. Although most health professionals questioned knew that AIDS is caused by an infectious agents, their knowledge of transmission routes, the "window period" and the length of the incubation period is still inadequate. Thus, health professionals in China urgently need both more training and more effective training. The effectiveness of future HIV/AIDS workshops should be evaluated.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Reversal of aberrant splicing of beta-thalassemia allele by antisense RNA in vitro and in vivo.

OBJECTIVE: To investigate the reversal of aberrant splicing of beta-thalassemia allele (IVS-2-654 C-->T, beta 654) by antisense RNA in vitro and in vivo. METHODS: The vector expressing antisense RNA which targeted against the aberrant splice sites of beta 654 pre-mRNA was constructed in pcDNA3, and then used to repair the defective splicing of the mutant pre-mRNA in an in vitro transcription and splicing system, as well as in HeLa beta 654 cells and cultured beta 654 erythroid cells by lipid-mediated DNA-transfection method. The effect of the antisense RNA was identified by RT-PCR mediated mRNA quantitative assay as well as globin chain microbiosynthesis. RESULTS: The antisense RNA decreased the aberrant splicing product and restored the correct splicing pattern in vitro and in vivo efficiently. In the in vitro transcription and splicing system, the level of normally spliced mRNA [beta/(beta + beta*)] increased from 0.25 to 0.60. In cultured HeLa beta 654 cells, the level of beta/(beta + beta*) increased from 0.07 to 0.43 on the 15th day after transfection. In cultured beta 654 erythroid cells, the level of mRNA [beta/(beta + beta*)] increased from 0.19 to 0.58 on the 8th day after transfection in beta 654/beta 654 erythroid cells, from 0.02 to 0.38 in beta 654/beta 41-42 erythroid cells, and from 0.45 to 0.83 in beta 654/beta A erythroid cells, respectively. Correspondingly, the ratios of globin chain (beta/alpha) biosynthesis increased from 0.16 to 0.52 on the 8th day after transfection in beta 654/beta 654 erythroid cells, 0.05 to 0.36 in beta 654/beta 41-42 erythroid cells, and 0.42 to 0.81 in beta 654/beta A erythroid cells, respectively. The splicing pattern did not show significant changes as compared to the untreated, as well as to the control antisense fragment. CONCLUSIONS: Antisense RNA transcribed from the expression vector described here could efficiently suppress the aberrant splicing pattern of beta 654 mutant mRNA and restore the correct splicing pathway in vitro and in vivo, leading to the improvement of globin chain biosynthesis in thalassemic cells. Our antisense strategy provides an alternative approach to the gene therapy of beta-thalassemia.

Adolescent↗
PubMed1999

[Clinical and experimental study of yushen jiangtang tablet in treating non-insulin dependent diabetes mellitus].

OBJECTIVE: To evaluate the therapeutic effect and safety of Yushen Jiangtang Tablet (YSJTT) in treating non-insulin dependent diabetes mellitus (NIDDM) of Qi-Yin Deficiency Syndrome (QYD). METHODS: One hundred and one patients of NIDDM with QYD were treated with YSJTT and compared with 60 patients of the control group treated with Shenqi Jiangtang Tablet. The experimental study on pharmacologic effect and toxicity of YSJTT was also conducted. RESULTS: The total effective rate of the YSJTT group was 87.12% and the markedly effective rate 44.55%, while those of the control group were 70.00% and 18.33% respectively, comparison between the two groups showed that the effect of the YSJTT group was superior to that of the control group, P < 0.01. No acute or chronic toxic or side effect was found in animal experiment. Pharmacologic study showed that YSJTT had obvious effect in decreasing blood glucose and serum triglyceride levels in rats with alloxan induced diabetes. CONCLUSION: YSJTT is effective in treating NIDDM, and apparent toxic-side effect of it was not found.

Adult↗